Bubble cap for gas and liquid contact apparatus



June 19, 1928. 1,673,895

c. M. ALEXANDER BUBBLE CAP FOR GAS AND LIQUID CONTACT APPARATUS Filed July 25. 19,26

9 :1 ill I L Gas INVENTOR VZLOT Cl we M Alexander y /3 BY L/gu/a ATTORNEYS Patented June 19, 1928.

UNITED, STATES CLIVE M. ALEXANDER, 0F WAXAHACEIE, TEXAS.

BUBBLE CA1 FOR GAS AND LIQUID CONTACT APPARATUS.

Application filed July 23,

This invention relates to improvements in gas and liquid or vapor and liquid contact apparatus. More particularly, the invention relates to improvements in bubble caps such as are used in fractionating. towers,

absorbing towers, scrubbing towers and the like where it is desired to contact a vapor or gas with a liquid. Towers for these several purposes are commonly made up. of a series of pans or trays in each of which a number or nipples are arranged, caps being arranged over the nipples to compel gas or vapor rising through the nipple to bubble under the rim or through openings in the side walls of the cap through a pool of liquid maintained on the, pan or tray, overflow connections also being provided to maintain a liquid level at or above the upper edges oi the openings through which the gas or vapor is discharged and to permit excess liquid to fiowto the next lower pan or tray in series. Various shapes of bubble caps have been employed for this purpose, some of them being supported on the rim of the cap and some by a connection between the crown of the cap and the nipple over which it is placed or the tray or pan itself.

This invention provides an improved bubble cap of special value and application in apparatus of the type just described which has several advantages. The improved bubble cap of the invention has a high ratio between the area of the openingsfor'the escape of gas or vapor and the space occupied by the cap, making'possible a larger capacity per pan or tray of a given area. The improved bubble cap of the invention also promotes more effective distribution of the gas or vapor escaping therefrom, making it possible to secure better contact between liquid and gas or vapor.

In the improved bubble cap of this invention, the side walls of the cap are provided with alternate extensions and depressions and openings for the escape of gas and vapor from beneath the cap are arranged through both extended and depressed portions of the side walls. A plurality .of series of openings for the escape of gas or vapor from beneath the cap is'thus provided, the several series of openings being arranged to discharge the gas or vapor at substantially diflerent distances from the vertical axis of the bubble cap. A high ratio as between the total width of the opening and the mean perimeter of the hub 1e cap/ is thus mainor scrubbing operations.

1926. Serial 1:5.124340.

tained, and distribution afl'ordingintimate contacting is promoted by discharge of the gas and vapor at' more or less separated points and in a manner to insure fine division of the gas and vapor.

The present invention is particularly ap- Elicable in connection with bubble caps made y casting and adapted to be supported on the pan or tray by the rim of the capitself. The present invention makes it possible to fabricate the bubble caps in this manner with a relatively large area of opening for the discharge of gas or vapor with respect to the size of the cap without sacrifice of the stren t-h of the cap or its ability toresist hand ing or cooling strains involved in casting through any necessity of making parts of the cap too light.

Two forms of bubble caps embodying the invention are diagrammatically illustrated in the accompanying drawing, and the invention will be further described in connection therewith, but it will be .understood that while the invention is exemplified by this further description and illustration it is not limited thereto. In the drawing Fig. l is an elevation, partly in section, of a bubble cap embodying the invention,

Fig. 2 is a plan view, with parts broken away, of the bubble cap shown in Fig- 1,

Fig. 3 is an elevation, partly in section, of a modified form of bubble cap .embodying the invention,

Fig. 4 is a plan view, with partsbroken away, of the bubble cap shown in Fig. 3, an

Fig. 5 is a diagrammatic representation, in elevation and partly in section, of a tower illustrating the use of theimproved bubble.

cap of the invention in apparatus of this character.

Referring to Fig. 5, the tower illustrated is of conventional construction such as is commonly used for fractionation, absorption It consists of a series of trays 6 through which nipples 7 extend. Bubble'caps 8 are arranged over the nipples so that gas or vapor rising through V the nipples is compelled to bubble through liquid maintained at a level above the discharge openings of the bubble caps by means of run-back connections 9 which also serve to convey excess liquid to the next lower tray. Gas or vapor to be supplied to treatment in a tower may, for example, be intro duced through connection 10 and any gas the side wall of the cap 15.

or vapor remaining uncondensed or unabsorbed may escape through connection 11. Liquid may be supplied through connection 12, and drawn oti, together with any constituents absorbed or condensed from the gas or vapor, through connection 13. E111- ployed as a iractionating tower, hot vapors may be supplied through connection 10, a condensed fraction separated in the tower and drawn ofi' through'connect'ion 13, and the uncondensed vapors discharged through connection 11. Employed as a scrubbing or absorption tower, the scrubbing or absor ent medium may be supplied through connection 12 while the gas or vapor mixture to be treated is supplied through connection 10, the absorbent or scrubbing medium charged with absorbed constituents then being drawn oil through connection 13 and the stripped gas or vapor mixture through connection 11.

The bubble caps illustrated in the drawing are of cast metal. Referring particularly to Figs. 1 and 2, a series of projections 14.- are arranged around the lower edge of Openings 16 for the escape of gas or vapor are provided between each of these projections and openings 17 for the escape of gas or vapor are also provided at the outer end of these pro- Jections. The adjacent openings are thus at a substantially diil'erentdistance from the vertical axis of the bubble cap, and a larger area of opening is provided than is possible, withoutsacrifice of the strength of the cap, in a bubble cap of ordinary construction with straight side walls. Referring part cularly to Figs. 3 and 4, aseries of projections 18 are provided on the side walls of the cap 19. Openings 20 for the escape of gas or vapor are provided in the side wall of the cap between each of these projections and a pair of openings 21 are provided in the lateral walls of each of the projections. The tops of the projections 18 are inclined upwardly toward the vertical axis "and intersect with the side walls of the bubble cap at a po nt appreciably higher than the upper extremity of the openings 20 located directly in the side of the main body of the bubble cap.

Gas and liquid or vapor and liquid contact apparatus equipped with bubble caps of this type ofler exceptionally low resistance to the flow of fluids therethrough due to the fact that the inclined tops of the projections 18 prevent the necessity of suddenly reversing the direction of flow of the major portion of the fluid entering through the nipple 7, and to the increased area of orifice openings directly from the main body of the bubble cap made possible by the increased height of the openings into the projections 18. Here also, an increased area of opening directly into the liquid is provided impossi-'.

ble in a cap of ordinary construction with straight side walls. At the same time, gas or vapor is discharged at a plurality 01 points at diiferent distances from the vertical axis of the cap in angularly directed streams promoting distribution and contact.

iVhile the bubble caps illustrated can easily be fabricated by casting, and while they are a particularly advantageous form for east bubble caps, it will be apparent that bubble caps embodying the invention can be faoricated in other ways. Likewise, the bubble caps shown are generally of circular configuration, but it will be apparent that caps of various shapes, square, triangular, hexagonal or rectangular may be constructed embodying the invention.

One of the important advantages of the bubble cap of the invention is that it provides for a high ratio between the total width of opening for the discharge of gas or vapor and the mean perimeter of the bubble cap, or the perimeter of a bubble cap of equal size of ordinary construction. In the bubble cap illustrated in Figs. 1 and Q, the total area of the opening for the escape of gas or vapor is in excess of 0.5 square inch per vertical inch of opening for each inch of perimeter of the largest circle, the largest regular eometrical figure, that can be drawn within tile points defined by the inner openings, and in that illustrated in Figs. 3 and 4, the total area of the opening on the basis of the same comparison is in excess of one square inch per vertical inch of opening. Both of these caps, it will be noted, are adapted to be supported on their rims. Another important advantage of the bubble cap of the invention is that it provides for such distribution of gas or vapor issuing therefrom that any tendency to form large bubbles with consequent reduction of contact surface between gas or vapor and liquid is minimized, insuring better contact and distribntion.

In one aspect, the improved bubble cap of the invention can be considered as making available for contact with gas or vapor discharge from each cap an annular ring of increased radial thickness of liquid on the tray in which the edge or rim of the cap is submerged. Referring to Fig. 1, for example, with a cap of ordinary construction with straight side walls, escaping vapor would be brought into contact only with liquid immediately about the edge of the cap, whereas with a cap constructed in accordance with this invention escaping vapor is brought into contact with liquid throughout a zone at least as wide as the distance between the inner openings 16 and the outer openings 17.

1 claim:

1. An improved bubble cap having irregular side walls with openings therethrough,

adjacent openings being non-adjoining and at substantially difiterent distances from the vertical axis of the bubble cap:

2. An improved bubble cap having a series of nolradjoining openings in the side walls thereof and an interposed series of openings projected a substantial distance beyond the first said series of openings, the openings of the last named series being non-adjoining with respect to each other and to the openings of the first named series.

An improved bubble cap having side walls with alternate extensions and depressions with openings through both extended and depressed portions thereof at substantially the same level and with openings from the main body of said bubble cap into the projecting portions thereof extending to a point substantially above the level of the openings in the depressed portions of said side walls.

4. An improve bubble cap having side walls with alternate extensions and depressions with openings through both extended and depressed portions thereof, the top of the extended portions inclining upwardly toward the vertical axis of the cap.

5. An improved bubble cap havin side walls with alternate extensions and depressions with openings through both extended and depressed portions thereof the total area of the openings from the main body of the bubble cap into the extended portions being substantially in excess of the total area of the openings in the depressed portions.

6. An improved bubble cap having side walls with alternate extensions and depress'ions with openings in both extended and depressed portions thereof, and means for feeding gas downwardly from the crown to the openings in said extended portions.

7 An improved bubble cap having side walls with alternate extensions and depressions, means for permitting the escape of gas from intermediate points in the side walls of both extended and depressed portions, and

n l means for withdrawing gas from the crown of said cap and transmitting it Without sudden change in the direction of flow to the openings in the extended portions.

8. An improved bubble cap having a series of non-adjoining openings through the side walls thereof at substantially different distances from the vertical axis, said side walls having a substantial change in direc tion between consecutive openings.

' In testimony whereof I affix my signature.

CLIVE M. ALEXANDER. 

